AHS CHEMISTRY GUTIERREZ

Slides:

Advertisements

Similar presentations

Calculate the Empirical Formula for a compound with the following composition: 46.16% carbon; 53.84% nitrogen 1)Change % to grams (if needed) 2)Convert.

Advertisements

Calculating Empirical and Molecular Formulas

Percent Composition and Empirical Formulas

Chemistry Notes Empirical & Molecular Formulas. Empirical Formula The empirical formula gives you the lowest, whole number ratio of elements in the compound.

Intro to Quantities Review Problems These are the calculations you should be able to perform: Sum of molar mass for a compound Convert mass  mole Convert.

Determining Chemical Formulas Experimentally % composition, empirical and molecular formula.

Determining Chemical Formulas

Molar Mass & Percent Composition

Mass Conservation in Chemical Reactions Mass and atoms are conserved in every chemical reaction. Molecules, formula units, moles and volumes are not always.

Percent Composition. What is Percent Composition?  The percent composition by mass of a compound represents the percent that each element in a compound.

PERCENT COMPOSITION. 2 3 Steps for Determining Chemical Formulas 1. Determine the percent composition of all elements. 2. Convert this information into.

Calculating Percentage Composition Suppose we wish to find the percent of carbon by mass in oxalic acid – H 2 C 2 O 4. 1.First we calculate the formula.

Chemistry There are some compounds that we know have elements in fixed mass proportions. Water H 2 O  2 g : 16 g Carbon dioxide CO 2 

1.2 Formulas Define the terms empirical formula and molecular formula Determine the empirical formula and/or the molecular formula of a given.

“Percent Composition and Chemical Formulas”

Lesson 27 Molecular Formula

Empirical and Molecular Formulas

Unit 5: The Mole.

Percent Composition (Section 11.4) Helps determine identity of unknown compound –Think CSI—they use a mass spectrometer Percent by mass of each element.

Chemical Formulas and Moles. Example: 1.water (C) – every molecule of water contains 2 atoms of hydrogen & one atom of oxygen - 2 molecules of H 2 O would.

STAAR Ladder to Success Rung 8. How do chemists define a mole? Example #1: A sample consists of 6.85 x atoms of carbon. How many moles does the.

Using the MOLE. Percentage composition Percentage composition is the mass of individual elements in a compound expressed as a percentage of the mass of.

Molar Mass Practice: Molar Mass Practice: 1. Find the molar mass of ammonium sulfate (also called the formula mass): 2. Find the molar mass of copper (II)

1 Chapter 10 “Chemical Quantities” Yes, you will need a calculator for this chapter!

Unit 6: Chemical Quantities

Percent Composition and Empirical Formula

Calculating Percent Composition From Formula % Composition: % by mass of each element in compound % Composition: % by mass of each element in compound.

Empirical & Molecular Formulas

Percent Composition. What is it? The percent composition by mass of a compound represents the percent that each element in a compound contributes to the.

The Mole, part II Glencoe, Chapter 11 Sections 11.3 & 11.4.

Mr. Chapman Chemistry 20. Converting from grams to moles Need: Moles and Mass worksheet.

Aim: How to calculate Percent Composition  DO NOW: 1. What is the number of moles of potassium chloride present in 148 g? 2. What is the molar mass of.

Empirical & Molecular Formulas. Percent Composition Determine the elements present in a compound and their percent by mass. A 100g sample of a new compound.

Percent Composition - The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component.

Percent Composition - The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component.

Percent Composition, Empirical and Molecular Formulas.

Percent Composition: Is the percentage of the total mass due to each element within a compound.

Percent Composition. – Compounds are ALWAYS composed of elements in fixed ratios. This is often referred to as the Law of Definite Proportions. – This.

Using Chemical Formulas

FINDING EMPIRICAL AND CHEMICAL FORMULAS BY EXPERIMENT

Empirical Formulas Definition Ex:

H.W. # 7 Study pp Ans. ques. p. 189 # 33, 34 p. 190 # 37,40,42

Chapter 3 Calculations with Chemical Formulas and Equations

AP CHEMISTRY NOTES Ch 3 Stoichiometry.

Percent Composition Percent by mass Element mass/compound mass x 100

Percentage Composition from Formulas

Aim: How to calculate Percent Composition

EMPIRICAL FORMULA AND MOLECULAR FORMULA

Using Chemical Formulas

Percent composition Empirical and molecular formulas

III. Formula Calculations

Percentage Composition

Empirical and molecular formulas

Percent Composition Empirical Formula Molecular Formula

Empirical Formulas Unit 5.

Percentage Composition

Vocabulary Percent Composition -

Percent Composition.

Empirical & Molecular Formulas

Percentage Composition

% Composition, Empirical and Molecular Formulas

Example Problems Ch

10.3 Percent Composition and Empirical Formula

Percent Composition.

Chemical Composition.

Chapter 11: More on the Mole

Reading Guide 10.3b Empirical Formulas Molecular Formulas

Notes Ch. 10.3a Calculating Percent Composition

Combustion analysis Combustion analysis is a method used in both organic chemistry and analytical chemistry to determine the elemental composition (more.

III. Percent Composition

Presentation transcript:

AHS CHEMISTRY GUTIERREZ 2013-2014 Percent Composition AHS CHEMISTRY GUTIERREZ 2013-2014 C.8.C Calculate percent composition and empirical and molecular formulas

Compounds Every chemical compound has a definite-a composition that is always the same wherever that compound is found. That means that: H2O (water) Will always have: 2 moles of hydrogen to every 1 mole of oxygen If you are studying a chemical compound, you may want to find the percent composition of a certain element within that chemical compound.

Percentage Composition The percentage composition of a compound is a statement of the relative mass each element contributes to the mass of the compound as a whole. Percent composition tells you by mass what percent of each element is present in a compound. It can be found using the following equation: Percent Composition by mass of an element mass of element in 1 mol of compound Molar mass of compound x 100 =

Steps to Finding Percent Composition Find the molar mass of all the elements in the compound in grams per mole. Find the molecular mass of the entire compound. Divide the component's molar mass by the entire molecular mass. You will now have a number between 0 and 1. Multiply it by 100 to get percent composition! Tips for solving: The compounds will always add up to 100%, so in a binary compound, you can find the % of the first element, then do 100%-(% first element) to get (% second element)

Therefore, HCl is 2.765 % Hydrogen and 97.235 % Chlorine by mass. Example Problem #1 What is the percent composition of hydrochloric acid (HCl)? Step 1. Find the molar mass of all elements H = 1.008 g and Cl= 35.453 Step 2. Now find the molecular mass of HCl 1.008 g + 35.453 g = 36.461 g Step 3. Divide the component's molar mass by the entire molecular mass and multiply by 100. (1.008 g/36.461 g) x 100 = 2.765% (35.453 g/ 36.461 g) x 100 = 97.235 % Therefore, HCl is 2.765 % Hydrogen and 97.235 % Chlorine by mass.

Example Problem #2

Now you Try! What are the percent composition of carbon and oxygen in carbon dioxide, CO2? Find the percent compositions of all of the elements in the following compounds, CuBr. Calculate the percent composition of nitrogen, hydrogen, and sulfur in (NH4)2S.

Answers mass % C = 27.29 % mass % O = 72.71 % Mass % Cu = 28.45% Mass % Br= 71.6% Mass% N= 41.1% Mass % H=11.8% Mass % S= 47.1%